Mott, the former Queensland and Victoria batsman then coach of New South Wales and Glamorgan, will link up with the Ireland squad in Australia on September 30 during their pre-World Cup tour and focus on working with the batsmen for a three-week period before rejoining at the start of the World Cup campaign in February.
Hopkinson, who has been involved with the England academy structure, is currently a coach with Sussex where he works with the second XI and also in a specialist capacity on the fielding, which is an area he will focus on with Ireland.
"Both bring exceptional sets of skills to the squad and will enhance the support staff significantly," Phil Simmons, the Ireland coach, said. "Matthew has extensive coaching experience both in Australia and abroad and comes with a proven reputation.
"Carl also is highly regarded in coaching circles with his work both domestically at Sussex, and internationally with the England U-19's and Lions squads."
Richard Holdsworth, Ireland's performance director, emphasised the importance of Mott's local knowledge. "It is important for our World Cup preparations and for the event itself that we have as many resources possible to help improve and support the squad.
"Matthew knows the Australian conditions well and has vast experience of playing on these surfaces, whilst Carl's experience in elite fielding should help sharpen the squad in this area."